The stresses on the heims and the links of the suspension are little to none while the car is just sitting there. The only reason to keep the car on jack stands during storage is to keep the tires from developing flat spots. Or, if you have really soft coils, to keep them from sagging. Also, I suppose that if you have the fancy do'da hiems with the self lubricating teflon liners, then it might be in the cards to even remove the links to keep the oils from being pressed out of one spot on the liner. But, we cant use those, so...